In her new book, “The End of the Suburbs,” Leigh Gallagher argues that the suburban way of life, once the epitome of the American dream, is becoming increasingly undesirable. Capital Business reporter Jonathan O’Connell, who has questioned whether Washington can grow up with its 20-somethings, chatted with Gallagher this past week about how Americans choose to live. An abridged version of that conversation follows.

O’Connell: Could you start by telling us why you think the suburbs are in decline?

Gallagher: The suburbs were a great idea that worked really well for a long time, but they overshot their mandate. We supersized everything in a way that led many people to live far away from where they needed to be and far away from their neighbors, and that has far-reaching implications, no pun intended. People have turned away from that kind of living. Add in the demographic forces that are reshaping our whole population, and the result is a significant shift. Census data shows that outward growth is slowing and inward growth is speeding up.

The early millennials are just getting into their mid-30s. How much do we know about whether millennials want to live in the suburbs?

That’s the billion-dollar question. All the studies show they want to live where they can walk, whether that’s the city or an urban suburb.

When I talk to home builders in the Washington area, some already recognize they are probably not going to be building anywhere near as many single-family, detached homes as in the past. But there are others who tell me: Every generation since World War II, when they became the heads of household and had children, wanted to live in single-family, detached homes on their own property, and there’s no reason to think that cycle has been broken.

Not yet. The millennials haven’t had kids yet. They’re delaying launching. But a lot of people think they’re not going to want cul-de-sac suburbia. They grew up in the back seats of cars, they know what it’s like to have to drive everywhere. They might not mind the suburbs, but they’re going to want the sort of suburb where you can walk to a cute diner.

I’m 34, I live in the District, and I’m a parent. A lot of my friends are thinking about schools and crime in terms of where they want to raise their families. Where do schools and crime fit in?

Crime is rising in suburbs and falling in cities. So crime is less of an issue.

Schools are really the biggest reason sending people out to the suburbs. I talked to so many people who apologized: “Yeah, we know it’s boring, we had to do it for the schools.”

But that’s changing, too. The birthrate is going down: We’re having fewer children than we used to nationwide. There are more baby boomers and seniors in suburbs than families with children, which is hard to believe. So you’re seeing schools merge or close. The taxpayer base in the suburbs is going to be increasingly made up of an older cohort. They don’t care about schools. They care about making traffic signs readable and supporting services that will drive older people around when they stop being able to drive.

Communities with good schools will continue to attract people with young kids, so you’ll end up with a patchwork, where some suburbs are known for having the best schools, and suburbs that don’t will have fewer and fewer families with children.

If the worst-planned suburbs end up with some of the worst schools, the worst transit, the worst amenities, what will happen to them?

If you’re talking about a suburb within a reasonable range of a city, it can survive if it has a thriving older population. It just won’t draw the young families that are a great economic force.

But the exurbs, where we already see zombie subdivisions and some depopulation, could become slums, which doesn’t make a whole lot of sense because of the cost of transportation, but it could happen. Other people think home construction was never very good in the most outward-reaching communities. They went up the quickest in the housing boom and are going to be the first to literally fall apart.

What are some things that could help a suburb reinvent itself?

A place people want to walk around. Organic, village-type environments that are how the suburbs started to begin with. Public transit also. People want out of their cars, especially millennials.

One criticism of these walkable, hip places is that they will be bastions for the wealthy, who can afford to live right next to whatever transit and amenities are most desirable.

That’s a fair criticism. Home building has become commoditized to the point where builders know how to shave away every cost behind the kinds of houses they build. When you change the model — building in a way that’s slightly smaller, mixing houses and retail — it does get more expensive.

But there are some models that are not bastions for yuppies.

I liked the little tangible things builders can do to make suburbs work: building porches on the front of houses, building houses not that far away from the sidewalk, having sidewalks in the first place.

How the design of a neighborhood and a house impact the social element of how we live is really interesting.

How do you interact with your West Village neighbors in New York?

They’re all investment bankers in their 20s. They’re more interested in talking on their cellphones and where the next party is.

Isn’t that the urban experience millennials crave, though? A reader suggested to me that even when we build walkable urban places where people can interact, everybody is talking on their cellphones and ignoring one another anyhow.

Millennials are going to be on their phones and texting no matter what. It’s better if they’re at least somewhat social while doing it.

What are the main differences between the way you grew up in suburban Pennsylvania and how your kids will grow up in the West Village?

I don’t know if I’ll be able to afford to raise kids in the West Village. But I grew up in a suburb of Philadelphia called Media, Pennsylvania, that has a lot of ingredients you don’t really see anymore. It has a trolley that’s not just for show — people actually take it into Philadelphia. It’s got this thriving State Street with tons of stores and restaurants.

My neighborhood abutted downtown Media. It was leafy and beautiful, old colonial houses. We all played in the triangle, where three streets converged, and had a great Fourth of July picnic there. That doesn’t really exist for a lot of people in the suburbs anymore.

Did nostalgia for your childhood play a role in your analysis of the future of the suburbs?

It did in that I didn’t come to this topic as somebody who really had it in for suburbia. I didn’t want to come off as some New York City condo-dwelling, espresso-drinking snob. I’m not like that. I’m nostalgic and see the potential suburbia had and how that’s changed.

This is a conversation between somebody who lives in a very nice portion of Manhattan and a person who lives in a pretty nice part of the District. Is it possible that the rest of the country likes driving around in cars and living in houses that are not that expensive?

They like living in houses that are not that expensive, but a lot of the drivey-drivey areas are really expensive because of the cost you put into getting around.

Studies show that people in older suburban neighborhoods, which were built on a different DNA, report greater levels of satisfaction. They’re healthier, they weigh less. It’s weird to correlate age of the neighborhood with health and happiness, but the blueprint for those neighborhoods is from before we put the whole experiment on steroids, and people lived better and happier.

I’ve peppered you with questions. Do you have any for me?

What do you think is going to happen in D.C., with the millennial situation in particular?

There are people building apartments as small as they possibly can. And instead of building many parking spaces, they’re building bicycle parking and car-sharing spots. They’re building cyber-cafes. All that is for primarily new college graduates. What happens at whatever age those people decide they want families? I don’t know that we know yet. But history has sort of shown they will want the same thing in a lot of ways that their parents wanted: the yard and the fence and the dog in the yard and all that.

I don’t think they’re going to come around to the very same thing they left.

I guess part of it is whether they grew up in a really boring, traffic-riddled suburb or a suburb like you or I grew up in. I have memories of being able to walk around and see kids on my block and play outside, which is something I’d like for my kids.

You can have that. The suburbs originally were supposed to be a combination of the city and the country. And we got urban sprawl. If suburbs got back to their roots, they’d make a lot of people happier.

One of the takeaways for me from your book was that there will be some winning suburbs and some losing suburbs. It’s maybe not the end of suburbs so much as the evolution of the suburbs.

Yes, absolutely. But it’s an end of a certain kind of suburb. I stand by that.

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